1. Field of the Invention
This invention is directed to methods for enhancing the quality of printing on resinated and non-resinated cotton fabrics using a colorant composition containing a pigment. Specifically, this invention is directed to methods of pretreating resinated and non-resinated cotton fabrics with an aqueous cellulase formulation prior to printing an image onto the fabric with a pigment composition so as to enhance printing qualities on the fabric such as pigment uptake. The methods disclosed herein generally entail treating cotton fabrics with an aqueous cellulase formulation followed by drying the fabrics and then printing an image onto the fabrics with a pigment composition.
2. State of the Art
Aesthetic and/or informational images are often placed on cotton fabrics with dye or pigment compositions by methods such as silk screening, painting, etc. While such methodology is well known in the art, these methods entail numerous problems which must be overcome in order to impart and retain quality images on cotton fabrics. Specifically, common with such printing methods is the low level of pigment uptake exhibited by some cotton fabrics. In general, the level of pigment uptake relates to the degree by which the pigment is incorporated (penetrates) into the fabric and can be indirectly measured by the number of passes required for sufficient amounts of the pigment composition to be incorporated into the cotton fabric to provide adequate resolution of the intended image. For some cotton fabrics, three passes are required to provide the desired level of pigment uptake. However, the use of numerous passes to ensure adequate pigment uptake poses problems such as ensuring that the second and additional passes are placed identically over the image created from the first pass so that blurring of the image does not occur.
Still another problem encountered with the methodology used for imparting an image onto a cotton fabric with a pigment composition is the level of adherence of the pigment composition to the fabric. Such adherence relates to the level of pigment incorporation into the fabric after fabric washing. Fabrics having low pigment adherence will exhibit reduced pigment retention after washing.
In any event, these problems impart a significant impediment to providing high quality cotton fabrics having images painted or silk-screened thereon with a pigment composition.
The present invention is directed to the discovery that pretreating cotton fabrics with an aqueous cellulase formulation, preferably under conditions of agitation, prior to printing an image on the fabric with a pigment composition, results in significant and unexpected improvements in the fabric. Specifically, printing images with a pigment composition on cotton fabrics pretreated with cellulase provides for increased pigment uptake by the fabric. In turn, this permits a reduction in the number of passes required to achieve a specific level of pigment uptake; or with the same number of passes as was previously employed with non-treated fabric, an increased amount of pigment is placed onto the fabric.
Additionally, the increased pigment uptake by the cellulase treated fabric is reflected in both the non-washed and washed fabrics (i.e., fabrics which after treatment with the pigment composition are washed in an aqueous detergent composition). The latter fact demonstrates that with cellulase treated fabrics, the pigment adheres strongly to the fabric.
While treatment of cotton fabrics with an aqueous cellulase formulation (including treatment under agitation) has heretofore been suggested in the art, there appears to be no suggestion in the art of using such conditions as a pretreatment for printing processes such as silk-screening and painting, using a pigment composition.